amr: be sure result of osmo_amr_bwe_to_oa() fits into int buf

osmo_amr_bwe_to_oa() uses an internal buffer with static size to store
intermediate results. The buffer is large enough for any real world
situation, but the check that tests if the result would fit into the
internal buffer is incorrect. It checks if there is enough room for the
existing payload, but does not include the expected growth of the
payload. Eventually the buffer could be overrun by one byte if one would
put a 256 byte long AMR payload.

Fixes: CID#195926
Change-Id: I4d7ac570a0b48368a82183673c46bca5f235f228

1 files changed, 1 insertions, 1 deletions

diff --git a/src/amr.c b/src/amr.c
index 9b423e8..9c63f60 100644
--- a/src/amr.c
+++ b/src/amr.c
@@ -158,7 +158,7 @@ int osmo_amr_bwe_to_oa(uint8_t *payload, unsigned int payload_len,
 	if (payload_len + 1 > payload_maxlen)
 		return -1;
 
-	if (payload_len > sizeof(buf))
+	if (payload_len + 1 > sizeof(buf))
 		return -1;
 
 	buf[0] = payload[0] & 0xf0;